Field of the Invention
The present invention generally relates to tomographic imaging and, more particularly, radio tomographic imaging.
Description of the Related Art
RADIO tomography or Radio Tomographic Imaging (RTI) is a method of using a network of radio transceivers to form a rough image of a region of interest for tracking movement patterns within the scene or mapping obstructions. It is analogous to Computed Tomography (CT) imaging, though on a much larger scale with much coarser resolution. As such, individuals or objects to be tracked do not need to carry radio emitters, they merely need to produce a radio shadow. The resulting imagery is privacy-sensitive, since personally identifying information cannot be extracted from the coarse image; available in all lighting and weather conditions; and available even when imaging through most wall construction materials.
In RTI, each transceiver in a network repeatedly sends short messages to all other transceivers. If an object is physically obstructing a given link, then the link's Received Signal Strength (RSS) will drop relative to calibration. By observing link attenuations, it is possible to determine which pixels of the resulting image are occupied and how dense the obstructions are relative to Radio Frequency (RF) propagation. The image formation process is similar to that in computed tomography imagery, with the differences lying in the propagation modeling and the somewhat sparser and more irregular placement of radio links in RTI.
Contemporary work regarding RTI is small but gradually increasing. The literature tends to focus on methods for producing better imagery or methods for tracking targets using RTI. However, as the number of sensors in a network is increased, computational complexity also increases. Resulting computational time for each image (frame) can be prohibitive to actual real time monitoring.
Accordingly, there is a need in the art for a system and method that addresses the computational complexity of radio tomographic imaging.